Laser beam quality improvement of REPUSIL-based rod amplifier with local short adiabatic taper (Conference Presentation)

Yuan Zhu; Martin Lorenz; Tina Eschrich; Martin Leich; Claudia Aichele; Jens Kobelke; Hartmut Bartelt; Matthias Jäger

doi:10.1117/12.2286895

14 March 2018 Laser beam quality improvement of REPUSIL-based rod amplifier with local short adiabatic taper (Conference Presentation)

Yuan Zhu, Martin Lorenz, Tina Eschrich, Martin Leich, Claudia Aichele, Jens Kobelke, Hartmut Bartelt, Matthias Jäger

Author Affiliations +

Proceedings Volume 10512, Fiber Lasers XV: Technology and Systems; 105121H (2018) https://doi.org/10.1117/12.2286895
Event: SPIE LASE, 2018, San Francisco, California, United States

Abstract

Fiber amplifiers with a robust monolithic seed coupling and very high peak power in a near diffraction-limited beam are increasingly demanded by many industrial applications in laser materials processing. A tapered all-solid rod-type fiber amplifier scheme is proposed. The principle of this approach is the use of a local adiabatic taper to provide a monolithic signal path and selectively excite the fundamental mode in highly multimode fiber. A large mode area fiber is used to scale up the peak power and suppress the nonlinear effects. The powder-sintering technology (REPUSIL) was employed to achieve rod-type fibers with excellent refractive index homogeneity. In this work, we present a double-clad Yb3+-doped rod-type REPUSIL fiber with a core/clad diameter of 45µm/190µm and a core/clad numerical aperture of 0.09/0.19.This developed fiber has a relatively low Al3+-concentration to reduce diffusion during tapering and an optimized outer cladding material to reduce the taper process temperature. Finally it is demonstrated that the diffusion phenomenon is successfully eliminated and the near-diffraction limited beam quality during the amplification process is maintained. First experiments with improved Yb3+-doped rod-type amplifiers delivered 2ns pulses with peak powers of 210kW for the non-tapered rod and 140kW for the tapered rod (limited by facet damage). For the tapered fiber, the beam quality was between 1.3 and 1.7, significantly improved compared to the beam quality of the non-tapered fiber (M2 = 3.3 ~ 4.5). Future work will concentrate on adopting endcaps to protect the fiber facets from damage while scaling up the peak power.

Conference Presentation

Citation Download Citation

Yuan Zhu, Martin Lorenz, Tina Eschrich, Martin Leich, Claudia Aichele, Jens Kobelke, Hartmut Bartelt, and Matthias Jäger "Laser beam quality improvement of REPUSIL-based rod amplifier with local short adiabatic taper (Conference Presentation)", Proc. SPIE 10512, Fiber Lasers XV: Technology and Systems, 105121H (14 March 2018); https://doi.org/10.1117/12.2286895

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available

Members: $17.00

Non-members: $21.00 ADD TO CART

PROCEEDINGS
PRESENTATION

WATCH
PRESENTATION SAVE TO MY LIBRARY

GET CITATION

KEYWORDS

Fiber amplifiers

Amplifiers

Diffusion

Fiber lasers

Laser processing

Multimode fibers

Tapered optical fibers

Keywords/Phrases

Search In:

Publication Years